• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.349-355
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• 2016

This study is about the reuse of bottom ash, which is released as a necessity in thermal power plant. In general, coal-ash are classified as fly-ash, bottom-ash, cinder-ash. Of these, a large amount of fly ash is being recycled as cement substitutes. While, recycling rates of bottom ash are the lowest due to its porosity and high absorption. In this study, the durability of the concrete using bottom ash as a concrete fine aggregate was evaluated. The using level of the bottom ash ranges to step-by-step from 0% to 30%. According to the result of the durability test, regardless of the presence of the bottom ash, freeze-thaw durability could be secured by air entrainment. In case of the resistance to chloride ions penetration, the length change, and the effects on heavy metals, the replacement of bottom ash as fine aggregate was not critical. Although carbonation penetration was higher as the replacement level of bottom ash increased, the experiment showed that it could be possible to use bottom ash as concrete fine aggregate with proper mix design.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.37-45
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• 2011

Purpose: Heat pressed ceramics, used for all ceramic restorations, have the additional advantage of being technically less change through using of the lost-wax technique. Conceptually, combining the ceramic with the clinically proven reinforcing ability of a metal framework would be advantageous; however, cause of mismatching of fusion between ceramics and metal frameworks which from differences of casting temperature and coefficient of thermal expansion, pressed ceramics could not be used with a metal framework. The purpose of this study was to compare shear bond strength of press-to metal ceramic to porcelain fused non precious metal and feldspatic porcelain fused non precious metal. Methods: The 30 metal specimens were casted in a porcelain fused non precious metal nickel-chromium alloy. They were divided into 3 groups by surface treatment and applied ceramic: $125{\mu}m$ aluminium oxide sandblasting and veneered feldspatic porcelain (group FP), $125{\mu}m$ aluminium oxide sandblasting and had press-to-metal ceramic applied (group PC), porcelain bonder (gold bonder) fused on surface of metal specimens and had press-to-metal ceramic applied (group PCG). In each group 10 metal specimens were used. The press-to-metal ceramic applied 20 specimens had ash-free wax pattern applied, the metal-wax complexes invested, and were pressed with heat press ceramic. All specimens were subjected to shear bond strength test at a crosshead speed of 1.0 mm/min. Results: The results of measured in Mean SD and data were analyzed by one-way AVOVA (p= .05) and Tukey HSD test (p= .05).: group FP $16.090{\pm}1.841$ MPa, group PC $12.620{\pm}1.8256$ MPa, group PCG $10.920{\pm}0.9283$, significant differences between all groups (p < .05). Significant differences were found in each between group FP and group PC, group FP and group PCG (p < .05). Conclusion: The shear bond strength of press-to-metal ceramic to porcelain fused non precious metal was described higher in unused gold bonder group than used gold bonder groups.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.1
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• pp.27-44
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• 2015

Objectives This study was carried out to find the effects of Gami-cheongyulsaseub-tang (hereinafter referred to GCST) on the inhibition of zymosan-induced pain in rats and collagen II-induced arthritis (CIA) in DBA/1J mouse. Methods As an acute inflammatory pain model, peripheral inflammation was induced by intraplantar injection of zymosan into the right hind paw in rats and then the hyperalgesia and pain regulating factors in spinal cord were analyzed. As a chronic inflammation model, the mixture of collagen II and complete Freund's adjuvant was treated into mice to establish rheumatoid arthritis and then body weight, thickness of hind paw, pathological change of spleen, immunological rheumatoid factor (IgG1, IgG2a, IgG2b, IgM and anti-collagen II), pro-inflammatory cytokines, and bone injury were analyzed. Results In the acute inflammatory pain model, GCST significantly inhibited the thermal and mechanical hyperalgesia and the pain regulating factors, including Fos, CD11b, PKA and PKC, in the spinal cord with a dose-dependent manner. In the chronic rheumatoid arthritis model, GCST administration decreased arthritic index and paw edema as compared with CIA control group. In particular, GCST reduced significantly the serum levels of total IgG2a, IgG2b, IgM, and specific anti-collagen II, but not total IgG1. GCST also resulted in the attenuation of bone injury and spleen enlargement/adhesion in CIA mice. Moreover, the secretion of pro-inflammatory cytokines TNF-${\alpha}$ and IL-$1{\beta}$ in CIA mice was significantly reduced by GCST in a dose-dependent manner. Conclusions Comparison of the results in this study showed that GCST had anti-nociceptive and immunomodulatory effects. These data imply that GCST can be used as an effective drug for not only rheumatoid arthritic pain but also other auto-immune diseases.

• Resources Recycling
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• v.24 no.2
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• pp.3-12
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• 2015

We researched characteristics of heat recovery rate and fouling according to structures and materials in heat exchangers like water preheater and air preheater. Economizer and air preheater have used in thermal electric power plant. we made small incinerator and heat exchangers to carry out simulated experiment. We observed fouling formation and change of heat recovery rate, combusting powdered coal for 24 hr. In economizer, fin tube type had the largest amount of fouling formation, followed by tube line type > pipe type > auto washing type according to structures. As heat recovery rate, fin tube showed highest recovery rate, followed by auto washing type > pipe type > tube line type. In air preheater, fin tube type had the largest amount of fouling formation, followed by fin plate type > pipe type > pipe type coated by teflon > pipe type coated by ceramic according to structures. And then, heat recovery rate showed the same oder.

• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.254-260
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• 2017

The purpose of this study is to evaluate the sound absorption characteristics of a human body according to the amount of clothing worn by using reverberation method measurement method for developing standard test dummy, which can be used for testing absorption of occupied audience chair. Test method was based on the previous study (Conti et al., 2004), each experiment is conducted in the reverberation room and a subject wearing clothes is standing in that chamber. In this experiment, the sound absorption area of each frequency band according to the wearing of various material clothing was measured. As a result of measurements, the average sound absorption area of the whole frequency band was $0.25m^2-0.48m^2$ in case of a subject not wearing outer clothes, and $0.38m^2-0.98m^2$ in case of wearing of outerwear. Polyester tops by showing the maximum value, the highest characteristics in the 800 Hz to 1 kHz band among the rest of fiber materials. The outer jacket made of the wool and cotton materials show a higher absorption area as the frequency increases to the higher frequency band. The change of the sound absorption area according to the clothing amount was divided by the thermal resistance (clo) of the worn clothes and the weight per body surface area.

• Clean Technology
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• v.20 no.4
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• pp.449-456
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• 2014

There has been increasing concerns for the problems of water security in countries, caused by the frequent occurrence of localized drought due to the climate change and uncertainty of water balance. The importance of fresh water is emphasized as considerable amount of usable fresh water is utilized for power generation sector producing electricity. PV power system, the source of renewable energy, consumes water for the every steps of life cycle: manufacturing, installation, and operation. However, it uses relatively less water than the traditional energy sources such as thermal power and nuclear power sources. In this study, to find out the use of water for the entire process of PV power system from extracting raw materials to operating the system, the footprint of water in the whole process is measured to be analyzed. Measuring the result, the PV water footprint of value chain was $0.989m^3/MWh$ and the water footprint appeared higher specially in poly-Si and solar cell process. The following two reasons explain it: poly-Si process is energy-intensive process and it consumes lots of cooling water. In solar cell process, deionized water is used considerably for washing a high-efficiency crystalline silicon. It is identified that PV system is the source using less water than traditional ones, which has a critical value in saving water. In discussing the future energy policy, it is vital to introduce the concept of water footprint as a supplementary value of renewable energy.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.270-280
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• 2014

In this study, to examine the causes of cracks in continuously reinforced concrete tracks (CRCTs) and the main factors affecting cracking, a field survey on the status of cracks and crack patterns in the Gyeong-bu high speed line was conducted, and the crack patterns of CRCT due to the temperature difference between the top of the slab (TCL) and the bottom of the subbase (HSB) and the drying shrinkage of concrete were predicted by a nonlinear finite element model considering the structure of CRCT. The results of the numerical analysis show that cracks will be developed at the interface between the sleeper and the TCL, and under the sleeper due to the temperature difference and concrete shrinkage. This corresponds well to the crack locations found in the field. Also, it is found that the most significant factors are the coefficient of thermal expansion with respect to the temperature difference, and the drying shrinkage strain with respect to shrinkage. According to the results, the reinforcement ratio should be carefully determined considering the structures of CRCT because the crack spacing is not always proportional to the reinforcement ratio due to the sleepers embedded in the TCL.

• Polymer(Korea)
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• v.37 no.4
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• pp.494-499
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• 2013

Modified polypropylene (m-PP) was fabricated by furfuryl sulphide (FS) as branching agent and m-PP/nano-filler composites were prepared with silicate and multi-walled carbon nanotube (MWCNT), using a twin screw extruder. The chemical structures and thermal properties of the m-PP were investigated by FTIR and DSC. The chemical structure of the m-PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 $cm^{-1}$. There was no district change in melting temperature in case of m-PP, but a certain increase in crystallization temperature was notified and the increase was in the range of $10-20^{\circ}C$. The rheological properties, filler dispersion and foaming behaviors of the m-PP/nano-filler composites were investigated by dynamic rheometer, X-ray diffractometer (XRD) and scanning/transmission electron microscope (SEM/TEM). m-PP/nano-filler composites showed a high complex viscosity at a low frequency, an increase in melt elasticity, and a high shear thinning effect. Compared to pure PP, m-PP and m-PP/nano-filler composites were sufficient to enhance the foaming behavior.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.213-218
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• 2014

Effects of elevated $CO_2$ on leaf phenology of Quercus acutissima were examined using open-top chambers, which had ambient and elevated $CO_2$ concentrations (ambient ${\times}1.4$, ambient ${\times}1.8$). To analyze the effect of chamber, non-treatment block was established near outside of the chambers. In 2013, budburst, leaf unfolding, coloring, and shedding were surveyed, and spring phenology was surveyed in 2014. Thermal sum (base temperature $+5^{\circ}C$) of each phenological event occurred was recorded. In addition, bud samples were collected and analyzed for carbohydrate contents in March 2014. Elevated $CO_2$ concentration advanced budburst and leaf unfolding, and delayed shedding in 2013. However, in 2014, the temperature of the spring season was high, and there was no significant effect of elevated $CO_2$ concentration on spring phenology. Carbohydrates content, such as starch, total non-structural carbohydrate and total soluble sugar, were significantly increased in response to elevated $CO_2$ concentration. It has been proposed that elevated $CO_2$ concentration could extend the growing season of temperate species with increased possibility of frost damage due to early bud opening and leaf unfolding. However, our analysis showed that the increased carbohydrate concentration in bud under elevated $CO_2$ would reduce the possibility of early spring frost damage by acting as cryoprotectant.

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.896-901
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• 2002

Since many process parameters of FHD(Flame Hydrolysis Deposition) are involved in forming multi-component amorphous silica film ($SiO_2-B_2O_3-P_2O_5-GeO_2$), it has not been easy to predict the optical, mechanical and thermal properties of deposited film from the simple process parameters, such as source flow rate. Furthermore, the prediction of final composition of film becomes even more difficult after sintering at high temperature due to the evaporation of volatile dopants. The motivation of the study was to clarify the quantitative relationship between simple process parameters such as the flow rate of source gases and resulting chemical composition of sintered film. Hence, the compositional analysis of silica soot by FTIR(Fourier Transformation Infrared Spectroscopy) and ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry) under the control of the amount of dopant was carried out to obtain the quantitative composition. By measuring spectrum of absorbance from FTIR, the compositional change of B-O, Si-O, OH($H_2O$) in silica film was measured. The concentrations of these dopants were also measured by ICP-AES, which were compared with the FTIR result. The final quantitative relationship between simple process parameters and composition was deduced from the comparison between two results.